An optical microfluidic platform for spatiotemporal biofilm treatment monitoring

Abstract

Bacterial biofilms constitute in excess of 65% of clinical microbial infections, with the antibiotic treatment of biofilm infections posing a unique challenge due to their high antibiotic tolerance. Recent studies performed in our group have demonstrated that a bioelectric effect featuring low-intensity electric signals combined with antibiotics can significantly improve the efficacy of biofilm treatment. In this work, we demonstrate the bioelectric effect using sub-micron thick planar electrodes in a microfluidic device. This is critical in efforts to develop microsystems for clinical biofilm infection management, including both in vivo and in vitro applications. Adaptation of the method to the microscale, for example, can enable the development of localized biofilm infection treatment using microfabricated medical devices, while augmenting existing capabilities to perform biofilm management beyond the clinical realm. Furthermore, due to scale-down of the system, the voltage requirement for inducing the electric field is reduced further below the media electrolysis threshold. Enhanced biofilm treatment using the bioelectric effect in the developed microfluidic device elicited a 56% greater reduction in viable cell density and 26% further decrease in biomass growth compared to traditional antibiotic therapy. This biofilm treatment efficacy, demonstrated in a micro-scale device and utilizing biocompatible voltage ranges, encourages the use of this method for future clinical biofilm treatment applications.

Microfluidic Microbial Bioelectrochemical Systems: An Integrated Investigation Platform for a More Fundamental Understanding of Electroactive Bacterial Biofilms

“…A wide range of microscopic techniques, from confocal microscopy [ 145 ] and scanning electrochemical microscopy [ 146 ] to spectroscopic techniques [ 139 , 147 , 148 ], have been successfully coupled into microfluidic platforms for live observation of biofilm. Other techniques can also be integrated, such as the widely studied optical density for quorum sensing analysis [ 149 , 150 ] or the innovative use of electrochemical imaging, where specific positions of a voltammogram are converted into pixels, enabling identification of redox currents and peak positions of an electroactive biofilm [ 151 ]. The combination of microbial engineering approaches, including matter balance transformation, target microbe selection, mutant characterization, and microbial function analysis, with microfluidic BESs will provide really new information as is already a trend in other domains exploring the activity and behavior of microorganisms in microfluidic study systems [ 140 ].…”

Approaches for Mitigating Microbial Biofilm-Related Drug Resistance: A Focus on Micro- and Nanotechnologies

“…Microfluidics involves the manipulation and control of a small amount of fluids in micrometer sized channels, which can be applied to understand the growth of biofilms on catheters via simulation of the local microenvironment [ 247 ]. Previous research utilizing microfluidics on biofilms include the study on biofilm formation and adhesion [ 248 ], effects of treatment [ 249 , 250 ], effects of synthetic QS [ 251 ], and effects of shear stress [ 252 ].…”

Microsystems for biofilm characterization and sensing – A review

“…Reproduced with permission from Ref. [ 102 ]. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)…”

“…Previous work conducted in our group showed that biofilm thickness can be determined using simple off-the shelf optoelectronic devices, such as photodiodes or CCD arrays, shown in Fig. 3 f–g [ 73 , 102 ]. Here, the optical density gives a direct measure of the biofilm thickness, while the CCD array functions in deriving the spatiotemporal thickness of the biofilms along the length of the channel.…”